Choose map: Ordering of maps by Map name sort lowercase after uppercase start letters

[kaputtnik]

Just stumbled over this by sorting maps by name with downloaded maps, because sometimes the used names are all lowercase. E.g. all maps uploaded by king_of_nowhere are all lowercase:

dolomites
fjords
to make the desert bloom

If you choose 'New game -> Choose map' and try to sort by map name, all those maps appear after the maps beginning with uppercase letters. E.g. 'dolomites' is shown after 'Wideworld' in the list.

[GunChleoc (gunchleoc)]

The problem is that we can't do real lexical sorting on simple strings. Our current sorting is just by character code point.

What we need to do here is to operate on the string classes provided by the ICU library. Once the work on the new font renderer is finished, we could start converting to ICU. I want to avoid too much conversion between std::strings and ICU strings and have kept this confined to the BiDi stuff so far.

[GunChleoc (gunchleoc)]

Migrated to https://github.com/widelands/widelands/issues/1669